Detecting new line character(s) in text file?

FROM : Jean-Nicolas Jolivet
DATE : Sat Nov 17 23:51:20 2007

My application deals with text files... each line has to be parsed so I
split it with

[str componentsSeparatedByString:@"\n"]

however..this only works if I have a text file that was saved on a
mac... Is there an easy way to determine which new line character is
used in a textfile (eighther linux, mac or win) and then use this for
parsing afterward?